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authorThadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>2014-10-24 01:19:35 +0400
committerMichael Ellerman <mpe@ellerman.id.au>2015-01-23 06:02:46 +0300
commit4e28784024a0d87f6f04250e46e8c9ac4f30e361 (patch)
treeab5cb3cb1768d5fafeb3021ad8ae1b6ae6d45017 /Documentation/kernel-parameters.txt
parent79872e35469b6db1c5243abded7b24367bd0a353 (diff)
downloadlinux-4e28784024a0d87f6f04250e46e8c9ac4f30e361.tar.xz
powernv/iommu: disable IOMMU bypass with param iommu=nobypass
When IOMMU bypass is enabled, a PCI device can read and write memory that was not mapped by the driver without causing an EEH. That might cause memory corruption, for example. When we disable bypass, DMA reads and writes to addresses not mapped by the IOMMU will cause an EEH, allowing us to debug such issues. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4df73da11adc..7dedfe56c3f3 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1493,6 +1493,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
forcesac
soft
pt [x86, IA-64]
+ nobypass [PPC/POWERNV]
+ Disable IOMMU bypass, using IOMMU for PCI devices.
io7= [HW] IO7 for Marvel based alpha systems